Abstract

Bacterial leaf blight (BLB) of paddy is caused by Xanthomonas oryzae pv.oryzae (Xoo), which leads to yield loss from 6 to 60%. Though chemicals and bactericides control BLB, they also cause several health and environmental hazards. Therefore, an alternative, cost effective, eco-friendly pest and pathogen control is the need of the hour. In the present investigation, cow urine extract, hexane, chloroform, ethyl acetate, alcohol, methanol and aqueous fractions ofPongamia pinnata Linn seed were tested against X. oryzae pv. oryzae for its antibacterial activity. Streptomycin sulphate (30 µg) and dimethyl sulfoxide (DMSO, 15 µL) are used as positive and negative control. All the extracts and fractions were effective and showed 10 to 13 mm zone of inhibition. Phytochemical analysis also showed the presence of terpenoids, quinine, coumarin, tannin and phenol, with flavonoid available in higher quantity (1.56 mgkg^-1).

Key words: Cow urine, Crude extract, Organic fraction, Xanthomonas, Zone of inhibition.